Conventional tank-mounted automotive fuel pumps typically have a rotary pumping element, 118 encased within a pump housing, 120, as shown in FIGS. 2 and 3. Fuel flows into pumping chamber 124 within pump housing 120 and the rotary pumping action of vanes 126 and vane grooves 128 of rotary pumping element 118 produces vortices 132. Vanes 126 do not, however, extend to the top, 130, of pumping chamber 124 and fuel crosses between sides 134 and 136 resulting in crossing losses which decrease pump efficiency.
An additional problem with conventional fuel pump designs is the need for stripper portion 122 in pump housing 120 (FIG. 2). As fuel is propelled by rotary pumping element 118 from the fuel inlet (not shown) to the fuel outlet (not shown), fuel pressure increases. Since the fuel inlet and fuel outlet are nearly circumferentially adjacent, stripper portion 122 must be closely toleranced with respect to rotary pumping element 118 so as to separate low pressure region 110 from high pressure region 112 near the inlet and outlet, respectively, without undue losses. Stripper portion 122 increases the manufacturing cost because close tolerancing is required.